Typhoon Nari has pummelled the northern Philippines, ripping roofs off buildings, killing five people and leaving more than two million people without electricity.

Nari hit the country's east coast around midnight local time, toppling trees and pylons and dumping heavy rain as it cut a westward swathe through the farming regions of the main island of Luzon.

"One of the dead was a police officer awaiting deployment for rescue duties. He was buried in a mudslide," National Disaster Risk Reduction and Management Council spokesman Rey Balido told a news conference in Manila.

Three people were crushed to death by falling trees while another person was electrocuted by a loose power line, he added.

The damage blacked out 37 towns and cities across central Luzon, according to a tally by the civil defence office in the region.

Road and utility crews were out clearing roads and restoring power, but it could take up to two days before electricity is restored and major highways are reopened to traffic.

A total of 2.1 million people live in the areas now without electricity, according to official population figures.